X-ray spectra by means of experimental data and Monte Carlo simulations for imaging applications

G. TIRAO; C. QUINTANA; F. MALANO; M. VALENTE

Rio de Janeiro

Congreso; XI Seminario Latinoamericano de Análisis por Técnicas de Rayos X; 2008

X-ray tubes have worldwide a wide range of applications, including several techniques for atomic physics, like X-ray fluorescence and medical imaging, like computed tomography. The performance of X-ray imaging detectors have shown to be significantly sensitive to the incident beam spectrum. Therefore, an accurate knowledge of the X-ray beam becomes necessary for the emission source characterization [1] and the whole imaging process comprehension. Direct measurements and suitable Monte Carlo simulations may be used in order to establish the X-ray spectra.. The experimental data have been achieved using a Si pin-diode detector (XR-100CR, Amptek Inc.,USA) and correcting to account for detector efficiency and spurious effects. A dedicated Monte Carlo simulation model, based on the PENELOPE code [2], has been developed in order to determine the Bremsstrahlung X-ray spectra [3,4], like those generated by conventional X-ray tubes (Mo and Cr). The simulated spectra have been suitably validated by comparison with the corresponding measured ones showing an overall good agreement. Different beam filters (copper and aluminium) have been inserted in order to evaluate the spectrum changes, due to the beam hardening effects, furthermore, attenuation curves have been obtained by means of both techniques. The influence of incident electron beam energy distribution on the generated X-ray Bremsstrahlung spectrum has been carefully studied with the validated Monte Carlo simulations. The obtained results may be useful for X-ray images, like absorption contrast improvement [5,6].